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Old 29th December 2011, 11:55 PM   #501
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For it to cut-out like that it must be something really simple stupid and obvious.
It wouldn't do that out of the factory gate!

[not meaning to be rude, rather to help narrow the search. Check all added solder joints, and then, all cheap and naasty aftermarket regs ]
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Old 30th December 2011, 12:24 AM   #502
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Oh God Simon
What does Brent think ?

Hope Martin is right and it's something easy
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Old 30th December 2011, 12:48 AM   #503
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- but honestly I didn't mean it as a pop at anyone, just a point of order. If we modify gear and find it less reliable as a result, it's something we've brought upon ourselves. Seek within.
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Old 30th December 2011, 07:51 AM   #504
SimontY is offline SimontY  United Kingdom
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Brent thought it might've been the clock wires causing interference but that should now be eliminated.

It's probably not a bad solder join as a) I've been very careful and often checked many of them and b) it sort of seems like the wrong behaviour for that, but of course it still could be!

I took the lid off and it's not cut out yet. More investigation is needed. I wonder if a regulator is getting too warm. Seeking within...
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Old 30th December 2011, 08:27 AM   #505
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Played it this morning... lasted almost 40mins with no interruptions and now won't play for more than a few seconds. That's not bad soldering to me, it must be heat-related, surely. Perhaps I need to look at the mechanism.
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Old 30th December 2011, 08:58 AM   #506
amc184 is offline amc184  New Zealand
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Yeah, the regulators are worth a check. I had a CD650 based player that broke the clip that holds the 5V regulator to the large heatsink. The regulator would overheat and its thermal shutdown would kick in, producing the symptoms exactly like what you said (it would appear to stop in the middle of playback, it was actually the player partially resetting as the 5V line went low). It was harder to spot as the regulator actually never burned, though I replaced it when I replaced the clip anyway.
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Old 30th December 2011, 09:05 AM   #507
SimontY is offline SimontY  United Kingdom
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Ahha, that's very interesting, thanks. I will have a look at all the regs, see what's cooking.
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Old 31st December 2011, 10:58 AM   #508
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Yep, very goood one.

Anotheridea learned the hard way - check you have at least suficient drop-out voltage across all the regs from input to output. It's usually 3.0v min for lm317/ 7805/7812/7905/7912/7x15ss etc; and especially possibly a bit more, very rarely less for aftermarket regs. ALWSRs for instance need a min. 5.0v due to the onboard pre-regulator, I'd expect similar 5v requirement for alternative regs if they use mosfet pass transistors.

Anyway if this overhead is tight or just under when the player is cold, then it can only take a small change on line voltage (or perhaps a small transformer running warm, or both) for a reg to drop out for regulation as the input voltage drops. That might be enough for something to fall over / the player to reset.
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Old 31st December 2011, 11:09 AM   #509
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Just remembered a follow-up point - when checking the voltage before the reg, use both DC and AC ranges on your meter. These things lie all the time You need enough DC voltage, AND for the apparent ripple to be small, so the troughs don't fall out well below the dropout voltage. This will go straight through the reg, feeding the load a much lower and noisier voltage than it appears.

I recently fixed a Naim XPS for a friend where the voltage readings made no sense whatsoever - plenty of DC voltage before a reg outputting 15vdc; connect the player, turn on, and the rail collaped to about 8v after the reg. The regulator tested fine when removed.

When I had the wit to hook-up the scope it became clear the raw rail had massive 100Hz ripple, infact the it was just the half-wave rectified sine returning to 0v 100times a second (the associated 10000uF reservoir cap had gone open-circuit inside the can after a nearby lightening strike). But the DVM still happily reported 22Vdc input, 15VDC output from the reg...
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Old 31st December 2011, 11:45 AM   #510
SimontY is offline SimontY  United Kingdom
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More things to check there then

If you have any ideas specifically related to warmth that would be much appreciated. The player is extremely consistent in its behaviour now. It plays for about 40mins then dies. If I turn it off to cool down / "rest" it then works again for a while till it warms up / "gets tired".

Once it has warmed up and "crashed" pressing play will only get it moving for a few seconds before it shuts down / resets again. Based on this it's surely temperature-related, but that could be regs, caps, mechanism grease, ceramic caps(??) etc.
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